Maxim's USB Emulator Consolidates In-Car Device Charging

Madison, Wisc. -- Carmakers are scrambling to keep up with the growing demand by drivers and passengers with portable devices who expect every car to accommodate their communication and entertainment needs. Against that backdrop, Maxim Integrated, an analog integration company, has found a new market opportunity.

For example, Maxim has developed an automotive-quality USB solution that can recognize and charge directly from the vehicle's battery any portable device people bring into a car. Maxim recently rolled out MAX 16984, an automotive-grade DC-DC converter with USB emulator.

Previously, many consumers were frustrated when they tried to charge their portable devices in cars. Typically, they found the process not so reliable, as witnessed by their iPhones not getting charged fast enough in a car.

Cars need to be prepared for a variety of scenarios to accommodate disparate devices. Carmakers also need a scalable solution because vehicles are now expected to accommodate, not just a single mobile device, but also a growing number of USB modules.

As Maxim explained, cars need to support the constantly evolving specifications of consumer devices, and they must offer charging and data transfer capabilities for those USB-equipped portable devices. Further, these mobile devices will require added protection so that they can reliably interface with the often harsh automotive environment, the company added.

More specifically, vehicles need a solution with an automotive-quality DC-DC converter that can drive up to 2.5 A with dynamic voltage adjustment, Maxim said. They require a USB charge emulator that can establish a handshake between a mobile device and upstream host instructing the mobile device to increase its charge current. The vehicles also need integrated electrostatic discharge (ESD) diodes and USB protection switches for automotive USB host applications.

Functions that used to be carried out by three separate ICs -- a separate power supply chip, a USB protection device and a device handing external functions -- are now integrated into one chip in MAX 16984, said Kent Robinett, Maxim’s Global Automotive Segment Leader.

It’s also important to note that passengers in a car aren’t always charging their devices or getting entertained by their mobile devices in the front seat. USB ports in the back seat mean that a passenger’s mobile device is placed at the end of three-meter embedded USB cables. The longer the distance, the likelier a drop in voltage and a reduction in charging current to happen. “That’s when adaptive voltage capability becomes important,” said Robinett.

He noted, by showing the chart below, that portable devices "will not charge properly, unless voltage drop across long captive cables is accounted for.

Maxim’s automotive-grade DC-DC converter with USB emulator is available today. For the standard Thin Quad Flat No Leads (TQFN) packaging, MAX16984 is priced at $3.92 in the volume of 1,000 units. For Maxim, whose automotive product strategy is to focus on solutions for EV/HEV battery, infotainment, smart key, and sensors, infotainment is definitely low-hanging fruit.

IHS Automotive’s senior analyst Luca DeAmbroggi earlier this year pegged total semiconductor revenue in 2013 derived from automotive infotainment will reach $6.67 billion. While this year’s growth is relatively “soft,” DeAmbroggi said, “Solid expansion returns next year and beyond, with revenue growth of 3 to 7 percent set to occur each year during the next five years.” The market research firm forecasts automotive infotainment semiconductor revenue worldwide to grow to $8.54 billion by 2018.

But speaking of mini-USB cables (see my post immediately below), did you know that they have five connections, not four? The fifth is for a pull-up resistor that lets the cable charge some devices. My daughter's MP3 player was one of those. The cable that came with it would only charge the player when connected to a computer USB port but not to a charger. Pin 4 needs a pull-up resistor so the charger knows there's something connected to it. PCB USB ports don't have that.

>more manufacturers would simply put usb chargers in the place of the lighter.

Don't take away my cigarette lighter socket even though I have never smoked and never will. Why, because what if you need to power something besides a phone charger? For example, my GPS plugs directly into the lighter socket. Now true, the other end of the cable is a mini-USB so I could use a mini-USB cable plugged into a USB socket, if my cars had them.

I would assume that with smoking on the decline (it is isn't it?) that more manufacturers would simply put usb chargers in the place of the lighter. Hell, even if smoking isn't on the decline, energy sucking devices are obviously on the rise.

>many consumers were frustrated when they tried to charge their portable devices in cars.

Well, it depends on how long you're in the car, doesn't it? If you take a 15 minute drive and you start with your phone at 20%, do you expect 100% in 15 minutes? Wou wonlt get that from a home charger. For less than about $15, you can get a dual charger that plugs into a cigarette lighter. I have a dual charger. Unless you're on a 2-hour drive, don't expect your phone to be fully charged.